Info on JNI exception handling

Hi,
Consider the scenario where a Java app uses JNI for accessing native methods.
I found one documentation saying that whenever environment related calls are made on the native side like
env->FindClass (DI_PROP);
we have to call functions env->ExceptionOccurred(), env->ExceptionDescribe(env) and env->ExceptionClear(env).
Can some one explain why this is required? Also is there any way to get the error string from env->ExceptionDescribe(env) so that it can be assigned to some string variable in code?
Regards,
Harish

The documention is precise. For FindClass for example, it is guaranteed that if the function fails, it both returns NULL and raises an exception; else it does neither. So you can detect failure either way.
But compare that to calling a regular Java method via CallIntMethod, for example. The return type is jint but the return value is actually undefined and meaningless if the method exited by throwing an exception rather than exiting normally. (At least that is implied by doc, which doesn't seem to say this explicitly.) Maybe the JVM returns 0 or some other magic value when a method throws, but I wouldn't assume so. (If I implemented a JVM, the return value in this case would be 42. :-)
-slj-

Similar Messages

Exception Handling In BPEL By using Catch Blocks or Fault Policies Or Both

I have a confusion regarding
Exception handling :
When Should i go for 1)Catch Block (Remote , or binding ) in bpel for exception handling .
2)Fault Policy , Fault binding.xml
Currently iam using catch blocks , but even fault policy is good , but can i use both...
Currently in My bpel ,when any error occurs i have to send a error notification by Email .
Currently i have exposed the email service which shuts emails and write a file with errored Message.
Hence if any error i will catch i in a parent BPEL, i will just invoke the above email, service .
So anybody can help me by giving the suggestion how to go for the best approach
Edited by: anantwag on Mar 23, 2011 6:31 AM

Currently in My bpel ,when any error occurs i have to send a error notification by Email .
Currently i have exposed the email service which shuts emails and write a file with errored Message.Seeing your use case I will suggest you to use fault handling framework (fault policy). Fault handling framework should be used where you need generic error handling framework which handles all the faults occured in any composite component. Generally BPEL catch block should be used to propagate error info/fault back to the client/to fault handling framework or to consume an error
Regards,
Anuj

How to implement this: Exception handler for managed bean

Hi, i'm using jdev 11g rel 1 , and i know i can use custom java class to extends DCErrorHandlerImpl, and override some method to customize the output or other info of my exceptions.
And then config it for databindings.cpx to make it available. But i found that this is only available for JboExceptions which are thrown from BC layer and through databindings.
If my exceptions are from managed bean, or just use application module to use the methods in it, while encounter exceptions, there's no way to handle it.
How can i handle it in managed bean in just one place(for architecuture layer)? <I just want to define a method to handle all managed bean's exceptions and use dcContainer.process it>,
who can give some suggestion?

If my exceptions are from managed bean, or just use application module to use the methods in it, while encounter exceptions, there's no way to handle it.
How can i handle it in managed bean in just one place(for architecuture layer)? <I just want to define a method to handle all managed bean's exceptions and use dcContainer.process it>,
who can give some suggestion?If you use application module methods in the managed bean, then use them through methodAction bindings so that the standard error handling works as expected.
See: http://blogs.oracle.com/smuenchadf/no_createrootappmodule_in_backing_beans.html
If you need to do a whole lot of error handling in the bean (instead of just showing a message once in a while), you might be putting too much business logic where it doesn't belong. Consider moving that logic to the AM

RFC: Exception handling

Hi there,
after playing a bit with external xml files provided by my
application i'm ready to go to the next topic on my ToDo-List.
How could one implement a good and stable technique for
exception handling? I'm talking about the interaction from spry to
our Web Framework which throws an error sometimes.
My current idea is that the server side framework could
return some kind of Error XML format which contains the exception
message and so on. This would require functions on client side to
precheck the server output.
Imho the best place for this is inside the XMLDataSet
constructor. When catching some bad XML file internal error
messages could be send using the already existing techniques OR by
providing an public function which then should be overriden by an
selfwritten one, e.g. to put it into my own `error box`.
Also, some kind of internal statemachine in XMLDataSet may
help a lot. That way each access to functions which aren't working
at the moment could be loggend and catched by an selfwritten
function.
I hope you get the idea,
what do you think?
Best regards,
Sebastian

Better error handling and error handling hooks is on the list
of things to do.
The way I see it, there are several types of errors that can
occur:
1. Server returns valid XML, but it's XML that describes an
error instead of the data requested.
- I believe this is what Sebastian was mentioning. I was
actually thinking of allowing a hook for developers to catch and
handle this case and perhaps leverage the states mechanism to let
them change the dynamic region markup used to display the error
since the data references in this error XML would be different.
2. The server returns an error. (Invalid URL or Server Error)
- This could be handled with states, but we need to expose
some data references, or set the data set to contain a known data
set schema that would allow the designer to show more info about
the error.
3. The server returns XML but uses a mime-type that is not
understood by Spy or the XML parsing code built-into the browser.
- I believe it was Doug [?] that had a patch that *always*
forced the data set to try and parse the XML string in the response
if the response didn't contain an XML DOM. My one paranoia about
that is that the server could actually be returning something that
is not XML, in which we would still fail and perhaps choke
somewhere else. I need to do some testing in that area.
I was thinking perhaps we should add something to the
XMLDataSet constructor that allowed a user to specify mime-types
for formats they knew were XML, but didn't use one of the standard
XML formats.
4. The browser chokes on "not-well-formed" XML.
- This is an interesting problem. IE silently fails when the
parser chokes, but Mozilla creates an XML DOM tree that reports the
error which does *not* match the XML string from the request
response. I had to add code to spry to detect when this happens.
5. An exception is thrown during Spry processing of XML data.
- This will require more programming on our part to handle
more cases.
--== Kin ==--

Regarding Exception handling in Coherence

Hi ,
I am using c++ to connecting coherence
try{
String::Handle gridHandleCache = GridCacheName;
if(hCommCache == NULL) {
hCommCache = CacheFactory::getCache(gridHandleCache);
else {
//cout<<"Info :"<<GridCacheName<<" Cache Already in Active State " <<endl;
catch(Exception::Handle vex) {
cout<<" coherence exe" ;
catch(std::exception e) {
cout<<e.what();
catch(...) {
cout <<"unknown exception" ;
When the error occurred (either runtime or other errors) i am always getting unname exception . it never enter into the Exception::Handle vex part.
when it will invoke catch(Exception::Handle vex) {. I want to separate runtime and connection error ecpetion sepeartyely.
May i know what would be the cause / or how to handle it seperately .
What are the errors are possible for connect / put/get/invoke(touchprocessor) . serializable cast ?
-Thanks
Edited by: 882600 on Aug 31, 2011 5:51 AM

Hi,
Still i have one issue
if i use RuntimeException::view or illegalArgumentException::view
catch(RuntimeException::view vex)
here i want to print string error message like
vseterror("%s",vex.getDescription() ) ; instead of cout<<vex
Is there any solution to print the error from view obj like e.what() char * / string type message ?
Is thie poisble to classify Confiuration error / Fatal error exceptions ?
Edited by: 882600 on Sep 6, 2011 12:57 PM
Edited by: 882600 on Sep 6, 2011 1:25 PM

Console Exception Handling. Allow another attempt for user before exiting

I am trying to implement a very simple program that prompts the user for info and reads in a few numbers. If the user accidentally enters a letter instead of a number I want the user to get another chance, not just execute the exception handler and exit the program (as it does now). I'd rather have the user get stuck in an endless loop waiting for valid input versus exiting on the first invalid entry.
The code I am using is something like this:
try{
   System.out.println("Enter a number?");
   int b=System.in.read();
   char c=(char) b;
   String s=String.valueOf(c);
   p.setDummyValue(Integer.parseInt(s) ); //**Possible Exception Here
catch(NumberFormatException e) {
   System.out.println("Invalid Input");
   // *** I'd love to somehow return to the "Enter a number" line from here
catch(IOException e) {
   //IO error code here
}Q: How can I implement the ability to allow a user to correct invalid input?
Thanks

Something like this should work:boolean numberValid = false;
while (!numberValid) {
     try {
          System.out.println("Enter a number?");
          int b=System.in.read();
          System.in.skip(System.in.available()); // skip carriage return
          char c=(char) b;
          String s=String.valueOf(c);
          p.setDummyValue(Integer.parseInt(s));
          numberValid = true;
     } catch(NumberFormatException e) {
          System.out.println("Invalid Input");
     } catch(IOException e) {
          //IO error code here
}

Exception Handling - sendEmail

Hi,
i'm trying to find out how the sendEmail service works.
it has an exception handling included which I've tried to test, but in case of a malformed emailaddress the process stops, I don't want to stop, I want to set an other action in case of this error.
I think of email addresses coming out of a db, where it isn't guaranteed that their format is ok.
Isn't it possible to handle such exceptions?
this is the eclipse-error-log entry.
!ENTRY com.adobe.DSC_Admin_UI 4 4 2008-01-16 14:06:08.208
!MESSAGE failed to invoke SendEmail.invoke
!STACK 0
java.io.InvalidClassException: javax.mail.MessagingException; local class incompatible: stream classdesc serialVersionUID = -6388198985190878204, local class serialVersionUID = -7569192289819959253
at com.adobe.idp.dsc.provider.impl.base.AbstractResponseHolder.handleException(AbstractRespo nseHolder.java:161)
at com.adobe.idp.dsc.provider.impl.soap.axis.sdk.SoapSdkBindingStubUtil.deSerializeResponse( SoapSdkBindingStubUtil.java:122)
at com.adobe.idp.dsc.provider.impl.soap.axis.sdk.SoapAxisDispatcher.doSend(SoapAxisDispatche r.java:128)
at com.adobe.idp.dsc.provider.impl.base.AbstractMessageDispatcher.send(AbstractMessageDispat cher.java:57)
regards
Johannes

I don't have a system in front of me, so I can't check this, but I'm reasonably sure that there is a little "lightning bolt" icon on the Email component. If you drag from here to another step in your process, and select the appropriate exception, I'm pretty sure your process will go to that step on the exception, rather than stalling.
If this doesn't work, then email info-at-avoka.com and I'll have a closer look.
Howard
http://www.avoka.com

ESB Exception handling

Dave,
In your Advanced Architecture presentation you mentioned about default and custom error handlers for non transactional end points. And you mentiond JMS:// and BPEL:// handlers as an example. So my question is how to configure this? I assume this involves editing ESB service files. Any documentation in this regard is appreciated. I know BPEL supports this via inbound activation specs but not sure about ESB.
By transactional you mean Asynch invocations, right? If I invoke a BPEL either via SOAP or internal Java binding, can I still use the exception handling for a Asynch invocation?
Thanks in advance.
Regards,
Rajesh

Hi Dave,
I checked this document yesterday, it contained 18 pages.
Some great info in the additional 7 pages, just in time as well: at a customer site we are hitting bug 5547165, the rejected messages being empty. I checked the rejection handlers for BPEL and was investigating how these could be used in case of ESB. Seems you have provided the answer.
Any chance a fix for the bug mentioned here is in the 10.1.3.3 patch set?
One more thing: by default the rejected messages for ESB are written to file system, in a directory below the 'home' OC4J instance. Could this be turned into a configurable space in a next release?
Thanks and best regards, Sjoerd

Exception handling strategy

hi,
i want to implement a very simple but effective exception handling strategy to aim -
1. log enough info for trouble shooting.
2. show single error page with message - something went wrong, try after some time.
this is how i am doing it:
for every try-catch block in my application, i am logging current exception & throwing a custom exception -
try {
// code
} catch(IOException e) {
e.printStackTrace();
throw new MyException();
in in my custom phase listener (implements PagePhaseListener), in beforePhase() method, i'll be catching MyException and redirecting user to error page.
try {
// code
} catch(MyException e) {
//redirect user to error page
please let me know what you guys think on this?
my exception class (does nothing as such) -
public class MyException extends Exception {
    public MyException(Throwable throwable) {
        super(throwable);
    public MyException(String string, Throwable throwable) {
        super(string, throwable);
    public MyException(String string) {
        super(string);
    public MyException() {
        super();
thanks.

hi,
i want to implement a very simple but effective exception handling strategy to aim -
1. log enough info for trouble shooting.
2. show single error page with message - something went wrong, try after some time.
this is how i am doing it:
for every try-catch block in my application, i am logging current exception & throwing a custom exception -
try {
// code
} catch(IOException e) {
e.printStackTrace();
throw new MyException();
in in my custom phase listener (implements PagePhaseListener), in beforePhase() method, i'll be catching MyException and redirecting user to error page.
try {
// code
} catch(MyException e) {
//redirect user to error page
please let me know what you guys think on this?
my exception class (does nothing as such) -
public class MyException extends Exception {
    public MyException(Throwable throwable) {
        super(throwable);
    public MyException(String string, Throwable throwable) {
        super(string, throwable);
    public MyException(String string) {
        super(string);
    public MyException() {
        super();
thanks.

Good exception handling policy for Java web application

I'm looking for a good exception handling policy for Java web application. First I found this Java exception handling best practices - How To Do In Java which says that you should never catch the Trowable class nor use e.printStackTrace();
Then I found this Oracle page The Message-Driven Bean Class - The Java EE 6 Tutorial, which does just that. So now I'm confused. Is there a good page online for an exception handling policy for Java EE Web applications? I have a hard time finding one. I've read that you should not catch the Exception class. I've been catching it previously to make sure that some unknown exception doesn't slip through early in the loop and stops all other customers from executing later on in the loop. We have a loop which runs once a minute implemented using the Quartz framework. Is it OK if you just change the implementation to catch the RuntimeException class instead of the Exception class? We're using Java 7 and the Jetty Servlet Container.

I'm looking for a good exception handling policy for Java web application.
If you have not done so I suggest you start by reviewing the several trails in The Java Tutorials.
Those trails cover both HOW to use exceptions and WHEN to use them.
This trail discusses the 'controversy' you mention regarding 'Unchecked Exceptions'
http://docs.oracle.com/javase/tutorial/essential/exceptions/runtime.html
Unchecked Exceptions — The Controversy
Because the Java programming language does not require methods to catch or to specify unchecked exceptions (RuntimeException, Error, and their subclasses), programmers may be tempted to write code that throws only unchecked exceptions or to make all their exception subclasses inherit from RuntimeException. Both of these shortcuts allow programmers to write code without bothering with compiler errors and without bothering to specify or to catch any exceptions. Although this may seem convenient to the programmer, it sidesteps the intent of the catch or specify requirement and can cause problems for others using your classes.
Why did the designers decide to force a method to specify all uncaught checked exceptions that can be thrown within its scope? Any Exception that can be thrown by a method is part of the method's public programming interface. Those who call a method must know about the exceptions that a method can throw so that they can decide what to do about them. These exceptions are as much a part of that method's programming interface as its parameters and return value.
The next question might be: "If it's so good to document a method's API, including the exceptions it can throw, why not specify runtime exceptions too?" Runtime exceptions represent problems that are the result of a programming problem, and as such, the API client code cannot reasonably be expected to recover from them or to handle them in any way. Such problems include arithmetic exceptions, such as dividing by zero; pointer exceptions, such as trying to access an object through a null reference; and indexing exceptions, such as attempting to access an array element through an index that is too large or too small.
Generally don't catch an exception unless you plan to HANDLE the exception. Logging, by itself is NOT handliing.
First I found this Java exception handling best practices - How To Do In Java which says that you should never catch the Trowable class nor use e.printStackTrace();
That article, like many, has some good advice and some poor or even bad advice. You get what you pay for!
I've read that you should not catch the Exception class.
Ok - but all that does is indicate that a problem of some sort happened somewhere. Not very useful info. Java goes to a lot of trouble to provide specific exceptions for specific problems.
I've been catching it previously to make sure that some unknown exception doesn't slip through early in the loop and stops all other customers from executing later on in the loop.
If the exception is 'unknown' then maybe it NEEDS to 'stop all other customers from executing later on in the loop'.
That is EXACTLY why you don't want to do that. You need to identify which exceptions should NOT stop processing and which ones should.
Some 'unknown' exceptions can NOT be recovered and indicate a serious problem, perhaps with the JVM itself. You can NOT just blindly keep executing and ignore them without risking data corruption and/or the integrity of the entire system Java is running on.
Is it OK if you just change the implementation to catch the RuntimeException class instead of the Exception class? We're using Java 7 and the Jetty Servlet Container.
No - not if you want a well-behaved system.
Don't catch exceptions unless you HANDLE/resolve them. There are times when it makes sense to log the exception (which does NOT handle it) and then raise it again so that it gets handled properly later. Yes - I know that is contrary to the advice given in that article but, IMHO, that article is wrong about that point.
If you have ever had to maintain/fix/support someone else's Java code you should already understand how difficult it can be to find WHERE a problem occurs and WHAT the exact problem is when exceptions are not handled properly.

MC.9 and MCY1 and Exception Handling in (Logistics Inf. Sys)LIS

Hi,
I want the 'Valuated Stock Value" greater then or equal to zero (>=) appear in the MC.9 report. I can create 'Exception' in MCY1 but am unable to do so. Once I am in MCY1; I choose 'Requirements' then Key Figure 'Valuated Stock Value' then 'Type of condition' is 'Threshold Val. Anal.' is set to '> 0'. However, the report still displays zero values in MC.9. I don't want to display 'Valuated Stock Value' zero to be displayed on the report. Please help.
Thanks
Naved

Hey Chris,
I got the point for exception handling in weblogic 9.2. We ae using 9.2. It comes up with the concept of shared page flows which means all my unhandled exceptions are thrown to the shared page flow controller. There based on the type of exception, i can forward the request to appropraite page.
Thanks anywyas,
Saurabh

PL/SQL 101 : Exception Handling

Frequently I see questions and issues around the use of Exception/Error Handling in PL/SQL. More often than not the issue comes from the questioners misunderstanding about how PL/SQL is constructed and executed, so I thought I'd write a small article covering the key concepts to give a clear picture of how it all hangs together. (Note: the examples are just showing examples of the exception handling structure, and should not be taken as truly valid code for ways of handling things)
Exception Handling
Contents
1. Understanding Execution Blocks (part 1)
2. Execution of the Execution Block
3. Exceptions
4. Understanding Execution Blocks (part 2)
5. How to continue exection of statements after an exception
6. User defined exceptions
7. Line number of exception
8. Exceptions within code within the exception block
1. Understanding Execution Blocks (part 1)
The first thing that one needs to understand is almost taking us back to the basics of PL/SQL... how a PL/SQL execution block is constructed.
Essentially an execution block is made of 3 sections...
+---------------------------+
|    Declaration Section    |
+---------------------------+
|    Statements Section    |
+---------------------------+
|     Exception Section     |
+---------------------------+
The Declaration section is the part defined between the PROCEDURE/FUNCTION header or the DECLARE keyword (for anonymous blocks) and the BEGIN keyword. (Optional section)
The Statements section is where your code goes and lies between the BEGIN keyword and the EXCEPTION keyword (or END keyword if there is no EXCEPTION section). (Mandatory section)
The Exception section is where any exception handling goes and lies between the EXCEPTION keyword at the END keyword. (Optional section)
Example of an anonymous block...
DECLARE
.. declarative statements go here ..
BEGIN
.. code statements go here ..
EXCEPTION
.. exception handlers go here ..
END;
Example of a procedure/function block...
[CREATE OR REPLACE] (PROCEDURE|FUNCTION) <proc or fn name> [(<parameters>)] [RETURN <datatype>] (IS|AS)
.. declarative statements go here ..
BEGIN
.. code statements go here ..
EXCEPTION
.. exception handlers go here ..
END;
(Note: The same can also be done for packages, but let's keep it simple)
2. Execution of the Execution Block
This may seem a simple concept, but it's surprising how many people have issues showing they haven't grasped it. When an Execution block is entered, the declaration section is processed, creating a scope of variables, types , cursors, etc. to be visible to the execution block and then execution enters into the Statements section. Each statment in the statements section is executed in turn and when the execution completes the last statment the execution block is exited back to whatever called it.
3. Exceptions
Exceptions generally happen during the execution of statements in the Statements section. When an exception happens the execution of statements jumps immediately into the exception section. In this section we can specify what exceptions we wish to 'capture' or 'trap' and do one of the two following things...
(Note: The exception section still has access to all the declared items in the declaration section)
3.i) Handle the exception
We do this when we recognise what the exception is (most likely it's something we expect to happen) and we have a means of dealing with it so that our application can continue on.
Example...
(without the exception handler the exception is passed back to the calling code, in this case SQL*Plus)
SQL> ed
Wrote file afiedt.buf
1 declare
2    v_name VARCHAR2(20);
3 begin
4    select ename
5    into   v_name
6    from   emp
7    where empno = &empno;
8    dbms_output.put_line(v_name);
9* end;
SQL> /
Enter value for empno: 123
old   7:   where empno = &empno;
new   7:   where empno = 123;
declare
ERROR at line 1:
ORA-01403: no data found
ORA-06512: at line 4
(with an exception handler, we capture the exception, handle it how we want to, and the calling code is happy that there is no error for it to report)
SQL> ed
Wrote file afiedt.buf
1 declare
2    v_name VARCHAR2(20);
3 begin
4    select ename
5    into   v_name
6    from   emp
7    where empno = &empno;
8    dbms_output.put_line(v_name);
9 exception
10    when no_data_found then
11      dbms_output.put_line('There is no employee with this employee number.');
12* end;
SQL> /
Enter value for empno: 123
old   7:   where empno = &empno;
new   7:   where empno = 123;
There is no employee with this employee number.
PL/SQL procedure successfully completed.
3.ii) Raise the exception
We do this when:-
a) we recognise the exception, handle it but still want to let the calling code know that it happened
b) we recognise the exception, wish to log it happened and then let the calling code deal with it
c) we don't recognise the exception and we want the calling code to deal with it
Example of b)
SQL> ed
Wrote file afiedt.buf
1 declare
2    v_name VARCHAR2(20);
3    v_empno NUMBER := &empno;
4 begin
5    select ename
6    into   v_name
7    from   emp
8    where empno = v_empno;
9    dbms_output.put_line(v_name);
10 EXCEPTION
11    WHEN no_data_found THEN
12      INSERT INTO sql_errors (txt)
13      VALUES ('Search for '||v_empno||' failed.');
14      COMMIT;
15      RAISE;
16* end;
SQL> /
Enter value for empno: 123
old   3:   v_empno NUMBER := &empno;
new   3:   v_empno NUMBER := 123;
declare
ERROR at line 1:
ORA-01403: no data found
ORA-06512: at line 15
SQL> select * from sql_errors;
TXT
Search for 123 failed.
SQL>
Example of c)
SQL> ed
Wrote file afiedt.buf
1 declare
2    v_name VARCHAR2(20);
3    v_empno NUMBER := &empno;
4 begin
5    select ename
6    into   v_name
7    from   emp
8    where empno = v_empno;
9    dbms_output.put_line(v_name);
10 EXCEPTION
11    WHEN no_data_found THEN
12      INSERT INTO sql_errors (txt)
13      VALUES ('Search for '||v_empno||' failed.');
14      COMMIT;
15      RAISE;
16    WHEN others THEN
17      RAISE;
18* end;
SQL> /
Enter value for empno: 'ABC'
old   3:   v_empno NUMBER := &empno;
new   3:   v_empno NUMBER := 'ABC';
declare
ERROR at line 1:
ORA-06502: PL/SQL: numeric or value error: character to number conversion error
ORA-06512: at line 3
SQL> select * from sql_errors;
TXT
Search for 123 failed.
SQL>
As you can see from the sql_errors log table, no log was written so the WHEN others exception was the exception that raised the error to the calling code (SQL*Plus)
4. Understanding Execution Blocks (part 2)
Ok, so now we understand the very basics of an execution block and what happens when an exception happens. Let's take it a step further...
Execution blocks are not just a single simple block in most cases. Often, during our statements section we have a need to call some reusable code and we do that by calling a procedure or function. Effectively this nests the procedure or function's code as another execution block within the current statement section so, in terms of execution, we end up with something like...
+---------------------------------+
|    Declaration Section          |
+---------------------------------+
|    Statements Section          |
|            .                    |
| +---------------------------+ |
| |    Declaration Section    | |
| +---------------------------+ |
| |    Statements Section    | |
| +---------------------------+ |
| |     Exception Section     | |
| +---------------------------+ |
|            .                    |
+---------------------------------+
|     Exception Section           |
+---------------------------------+
Example... (Note: log_trace just writes some text to a table for tracing)
SQL> create or replace procedure a as
2    v_dummy NUMBER := log_trace('Procedure A''s Declaration Section');
3 begin
4    v_dummy := log_trace('Procedure A''s Statement Section');
5    v_dummy := 1/0; -- cause an exception
6 exception
7    when others then
8      v_dummy := log_trace('Procedure A''s Exception Section');
9      raise;
10 end;
11 /
Procedure created.
SQL> create or replace procedure b as
2    v_dummy NUMBER := log_trace('Procedure B''s Declaration Section');
3 begin
4    v_dummy := log_trace('Procedure B''s Statement Section');
5    a; -- HERE the execution passes to the declare/statement/exception sections of A
6 exception
7    when others then
8      v_dummy := log_trace('Procedure B''s Exception Section');
9      raise;
10 end;
11 /
Procedure created.
SQL> exec b;
BEGIN b; END;
ERROR at line 1:
ORA-01476: divisor is equal to zero
ORA-06512: at "SCOTT.B", line 9
ORA-06512: at line 1
SQL> select * from code_trace;
TXT
Procedure B's Declaration Section
Procedure B's Statement Section
Procedure A's Declaration Section
Procedure A's Statement Section
Procedure A's Exception Section
Procedure B's Exception Section
6 rows selected.
SQL>
Likewise, execution blocks can be nested deeper and deeper.
5. How to continue exection of statements after an exception
One of the common questions asked is how to return execution to the statement after the one that created the exception and continue on.
Well, firstly, you can only do this for statements you expect to raise an exception, such as when you want to check if there is no data found in a query.
If you consider what's been shown above you could put any statement you expect to cause an exception inside it's own procedure or function with it's own exception section to handle the exception without raising it back to the calling code. However, the nature of procedures and functions is really to provide a means of re-using code, so if it's a statement you only use once it seems a little silly to go creating individual procedures for these.
Instead, you nest execution blocks directly, to give the same result as shown in the diagram at the start of part 4 of this article.
SQL> ed
Wrote file afiedt.buf
1 create or replace procedure b (p_empno IN VARCHAR2) as
2    v_dummy NUMBER := log_trace('Procedure B''s Declaration Section');
3 begin
4    v_dummy := log_trace('Procedure B''s Statement Section');
5    -- Here we start another execution block nested in the first one...
6    declare
7      v_dummy NUMBER := log_trace('Nested Block Declaration Section');
8    begin
9      v_dummy := log_trace('Nested Block Statement Section');
10      select empno
11        into   v_dummy
12        from   emp
13       where empno = p_empno; -- Note: the parameters and variables from
                                     parent execution block are available to use!
14    exception
15      when no_data_found then
16        -- This is an exception we can handle so we don't raise it
17        v_dummy := log_trace('No employee was found');
18        v_dummy := log_trace('Nested Block Exception Section - Exception Handled');
19      when others then
20        -- Other exceptions we can't handle so we raise them
21        v_dummy := log_trace('Nested Block Exception Section - Exception Raised');
22        raise;
23    end;
24    -- ...Here endeth the nested execution block
25    -- As the nested block handled it's exception we come back to here...
26    v_dummy := log_trace('Procedure B''s Statement Section Continued');
27 exception
28    when others then
29      -- We'll only get to here if an unhandled exception was raised
30      -- either in the nested block or in procedure b's statement section
31      v_dummy := log_trace('Procedure B''s Exception Section');
32      raise;
33* end;
SQL> /
Procedure created.
SQL> exec b(123);
PL/SQL procedure successfully completed.
SQL> select * from code_trace;
TXT
Procedure B's Declaration Section
Procedure B's Statement Section
Nested Block Declaration Section
Nested Block Statement Section
No employee was found
Nested Block Exception Section - Exception Handled
Procedure B's Statement Section Continued
7 rows selected.
SQL> truncate table code_trace;
Table truncated.
SQL> exec b('ABC');
BEGIN b('ABC'); END;
ERROR at line 1:
ORA-01722: invalid number
ORA-06512: at "SCOTT.B", line 32
ORA-06512: at line 1
SQL> select * from code_trace;
TXT
Procedure B's Declaration Section
Procedure B's Statement Section
Nested Block Declaration Section
Nested Block Statement Section
Nested Block Exception Section - Exception Raised
Procedure B's Exception Section
6 rows selected.
SQL>
You can see from this that, very simply, the code that we expected may have an exception was able to either handle the exception and return to the outer execution block to continue execution, or if an unexpected exception occurred then it was able to be raised up to the outer exception section.
6. User defined exceptions
There are three sorts of 'User Defined' exceptions. There are logical situations (e.g. business logic) where, for example, certain criteria are not met to complete a task, and there are existing Oracle errors that you wish to give a name to in order to capture them in the exception section. The third is raising your own exception messages with our own exception numbers. Let's look at the first one...
Let's say I have tables which detail stock availablility and reorder levels...
SQL> select * from reorder_level;
   ITEM_ID STOCK_LEVEL
         1          20
         2          20
         3          10
         4           2
         5           2
SQL> select * from stock;
   ITEM_ID ITEM_DESC STOCK_LEVEL
         1 Pencils             10
         2 Pens                 2
         3 Notepads            25
         4 Stapler              5
         5 Hole Punch           3
SQL>
Now, our Business has told the administrative clerk to check stock levels and re-order anything that is below the re-order level, but not to hold stock of more than 4 times the re-order level for any particular item. As an IT department we've been asked to put together an application that will automatically produce the re-order documents upon the clerks request and, because our company is so tight-ar*ed about money, they don't want to waste any paper with incorrect printouts so we have to ensure the clerk can't order things they shouldn't.
SQL> ed
Wrote file afiedt.buf
1 create or replace procedure re_order(p_item_id NUMBER, p_quantity NUMBER) is
2    cursor cur_stock_reorder is
3      select s.stock_level
4            ,r.stock_level as reorder_level
5            ,(r.stock_level*4) as reorder_limit
6      from stock s join reorder_level r on (s.item_id = r.item_id)
7      where s.item_id = p_item_id;
8    --
9    v_stock cur_stock_reorder%ROWTYPE;
10 begin
11    OPEN cur_stock_reorder;
12    FETCH cur_stock_reorder INTO v_stock;
13    IF cur_stock_reorder%NOTFOUND THEN
14      RAISE no_data_found;
15    END IF;
16    CLOSE cur_stock_reorder;
17    --
18    IF v_stock.stock_level >= v_stock.reorder_level THEN
19      -- Stock is not low enough to warrant an order
20      DBMS_OUTPUT.PUT_LINE('Stock has not reached re-order level yet!');
21    ELSE
22      IF v_stock.stock_level + p_quantity > v_stock.reorder_limit THEN
23        -- Required amount is over-ordering
24        DBMS_OUTPUT.PUT_LINE('Quantity specified is too much. Max for this item: '
                                 ||to_char(v_stock.reorder_limit-v_stock.stock_level));
25      ELSE
26        DBMS_OUTPUT.PUT_LINE('Order OK. Printing Order...');
27        -- Here goes our code to print the order
28      END IF;
29    END IF;
30    --
31 exception
32    WHEN no_data_found THEN
33      CLOSE cur_stock_reorder;
34      DBMS_OUTPUT.PUT_LINE('Invalid Item ID.');
35* end;
SQL> /
Procedure created.
SQL> exec re_order(10,100);
Invalid Item ID.
PL/SQL procedure successfully completed.
SQL> exec re_order(3,40);
Stock has not reached re-order level yet!
PL/SQL procedure successfully completed.
SQL> exec re_order(1,100);
Quantity specified is too much. Max for this item: 70
PL/SQL procedure successfully completed.
SQL> exec re_order(2,50);
Order OK. Printing Order...
PL/SQL procedure successfully completed.
SQL>
Ok, so that code works, but it's a bit messy with all those nested IF statements. Is there a cleaner way perhaps? Wouldn't it be nice if we could set up our own exceptions...
SQL> ed
Wrote file afiedt.buf
1 create or replace procedure re_order(p_item_id NUMBER, p_quantity NUMBER) is
2    cursor cur_stock_reorder is
3      select s.stock_level
4            ,r.stock_level as reorder_level
5            ,(r.stock_level*4) as reorder_limit
6      from stock s join reorder_level r on (s.item_id = r.item_id)
7      where s.item_id = p_item_id;
8    --
9    v_stock cur_stock_reorder%ROWTYPE;
10    --
11    -- Let's declare our own exceptions for business logic...
12    exc_not_warranted EXCEPTION;
13    exc_too_much      EXCEPTION;
14 begin
15    OPEN cur_stock_reorder;
16    FETCH cur_stock_reorder INTO v_stock;
17    IF cur_stock_reorder%NOTFOUND THEN
18      RAISE no_data_found;
19    END IF;
20    CLOSE cur_stock_reorder;
21    --
22    IF v_stock.stock_level >= v_stock.reorder_level THEN
23      -- Stock is not low enough to warrant an order
24      RAISE exc_not_warranted;
25    END IF;
26    --
27    IF v_stock.stock_level + p_quantity > v_stock.reorder_limit THEN
28      -- Required amount is over-ordering
29      RAISE exc_too_much;
30    END IF;
31    --
32    DBMS_OUTPUT.PUT_LINE('Order OK. Printing Order...');
33    -- Here goes our code to print the order
34    --
35 exception
36    WHEN no_data_found THEN
37      CLOSE cur_stock_reorder;
38      DBMS_OUTPUT.PUT_LINE('Invalid Item ID.');
39    WHEN exc_not_warranted THEN
40      DBMS_OUTPUT.PUT_LINE('Stock has not reached re-order level yet!');
41    WHEN exc_too_much THEN
42      DBMS_OUTPUT.PUT_LINE('Quantity specified is too much. Max for this item: '
                              ||to_char(v_stock.reorder_limit-v_stock.stock_level));
43* end;
SQL> /
Procedure created.
SQL> exec re_order(10,100);
Invalid Item ID.
PL/SQL procedure successfully completed.
SQL> exec re_order(3,40);
Stock has not reached re-order level yet!
PL/SQL procedure successfully completed.
SQL> exec re_order(1,100);
Quantity specified is too much. Max for this item: 70
PL/SQL procedure successfully completed.
SQL> exec re_order(2,50);
Order OK. Printing Order...
PL/SQL procedure successfully completed.
SQL>
That's better. And now we don't have to use all those nested IF statements and worry about it accidently getting to code that will print the order out as, once one of our user defined exceptions is raised, execution goes from the Statements section into the Exception section and all handling of errors is done in one place.
Now for the second sort of user defined exception...
A new requirement has come in from the Finance department who want to have details shown on the order that show a re-order 'indicator' based on the formula ((maximum allowed stock - current stock)/re-order quantity), so this needs calculating and passing to the report...
SQL> ed
Wrote file afiedt.buf
1 create or replace procedure re_order(p_item_id NUMBER, p_quantity NUMBER) is
2    cursor cur_stock_reorder is
3      select s.stock_level
4            ,r.stock_level as reorder_level
5            ,(r.stock_level*4) as reorder_limit
6            ,(((r.stock_level*4)-s.stock_level)/p_quantity) as finance_factor
7      from stock s join reorder_level r on (s.item_id = r.item_id)
8      where s.item_id = p_item_id;
9    --
10    v_stock cur_stock_reorder%ROWTYPE;
11    --
12    -- Let's declare our own exceptions for business logic...
13    exc_not_warranted EXCEPTION;
14    exc_too_much      EXCEPTION;
15 begin
16    OPEN cur_stock_reorder;
17    FETCH cur_stock_reorder INTO v_stock;
18    IF cur_stock_reorder%NOTFOUND THEN
19      RAISE no_data_found;
20    END IF;
21    CLOSE cur_stock_reorder;
22    --
23    IF v_stock.stock_level >= v_stock.reorder_level THEN
24      -- Stock is not low enough to warrant an order
25      RAISE exc_not_warranted;
26    END IF;
27    --
28    IF v_stock.stock_level + p_quantity > v_stock.reorder_limit THEN
29      -- Required amount is over-ordering
30      RAISE exc_too_much;
31    END IF;
32    --
33    DBMS_OUTPUT.PUT_LINE('Order OK. Printing Order...');
34    -- Here goes our code to print the order, passing the finance_factor
35    --
36 exception
37    WHEN no_data_found THEN
38      CLOSE cur_stock_reorder;
39      DBMS_OUTPUT.PUT_LINE('Invalid Item ID.');
40    WHEN exc_not_warranted THEN
41      DBMS_OUTPUT.PUT_LINE('Stock has not reached re-order level yet!');
42    WHEN exc_too_much THEN
43      DBMS_OUTPUT.PUT_LINE('Quantity specified is too much. Max for this item: '
                              ||to_char(v_stock.reorder_limit-v_stock.stock_level));
44* end;
SQL> /
Procedure created.
SQL> exec re_order(2,40);
Order OK. Printing Order...
PL/SQL procedure successfully completed.
SQL> exec re_order(2,0);
BEGIN re_order(2,0); END;
ERROR at line 1:
ORA-01476: divisor is equal to zero
ORA-06512: at "SCOTT.RE_ORDER", line 17
ORA-06512: at line 1
SQL>
Hmm, there's a problem if the person specifies a re-order quantity of zero. It raises an unhandled exception.
Well, we could put a condition/check into our code to make sure the parameter is not zero, but again we would be wrapping our code in an IF statement and not dealing with the exception in the exception handler.
We could do as we did before and just include a simple IF statement to check the value and raise our own user defined exception but, in this instance the error is standard Oracle error (ORA-01476) so we should be able to capture it inside the exception handler anyway... however...
EXCEPTION
WHEN ORA-01476 THEN
... is not valid. What we need is to give this Oracle error a name.
This is done by declaring a user defined exception as we did before and then associating that name with the error number using the PRAGMA EXCEPTION_INIT statement in the declaration section.
SQL> ed
Wrote file afiedt.buf
1 create or replace procedure re_order(p_item_id NUMBER, p_quantity NUMBER) is
2    cursor cur_stock_reorder is
3      select s.stock_level
4            ,r.stock_level as reorder_level
5            ,(r.stock_level*4) as reorder_limit
6            ,(((r.stock_level*4)-s.stock_level)/p_quantity) as finance_factor
7      from stock s join reorder_level r on (s.item_id = r.item_id)
8      where s.item_id = p_item_id;
9    --
10    v_stock cur_stock_reorder%ROWTYPE;
11    --
12    -- Let's declare our own exceptions for business logic...
13    exc_not_warranted EXCEPTION;
14    exc_too_much      EXCEPTION;
15    --
16    exc_zero_quantity EXCEPTION;
17    PRAGMA EXCEPTION_INIT(exc_zero_quantity, -1476);
18 begin
19    OPEN cur_stock_reorder;
20    FETCH cur_stock_reorder INTO v_stock;
21    IF cur_stock_reorder%NOTFOUND THEN
22      RAISE no_data_found;
23    END IF;
24    CLOSE cur_stock_reorder;
25    --
26    IF v_stock.stock_level >= v_stock.reorder_level THEN
27      -- Stock is not low enough to warrant an order
28      RAISE exc_not_warranted;
29    END IF;
30    --
31    IF v_stock.stock_level + p_quantity > v_stock.reorder_limit THEN
32      -- Required amount is over-ordering
33      RAISE exc_too_much;
34    END IF;
35    --
36    DBMS_OUTPUT.PUT_LINE('Order OK. Printing Order...');
37    -- Here goes our code to print the order, passing the finance_factor
38    --
39 exception
40    WHEN exc_zero_quantity THEN
41      DBMS_OUTPUT.PUT_LINE('Quantity of 0 (zero) is invalid.');
42    WHEN no_data_found THEN
43      CLOSE cur_stock_reorder;
44      DBMS_OUTPUT.PUT_LINE('Invalid Item ID.');
45    WHEN exc_not_warranted THEN
46      DBMS_OUTPUT.PUT_LINE('Stock has not reached re-order level yet!');
47    WHEN exc_too_much THEN
48      DBMS_OUTPUT.PUT_LINE('Quantity specified is too much. Max for this item: '
                              ||to_char(v_stock.reorder_limit-v_stock.stock_level));
49* end;
SQL> /
Procedure created.
SQL> exec re_order(2,0);
Quantity of 0 (zero) is invalid.
PL/SQL procedure successfully completed.
SQL>
Lastly, let's look at raising our own exceptions with our own exception numbers...
SQL> ed
Wrote file afiedt.buf
1 create or replace procedure re_order(p_item_id NUMBER, p_quantity NUMBER) is
2    cursor cur_stock_reorder is
3      select s.stock_level
4            ,r.stock_level as reorder_level
5            ,(r.stock_level*4) as reorder_limit
6            ,(((r.stock_level*4)-s.stock_level)/p_quantity) as finance_factor
7      from stock s join reorder_level r on (s.item_id = r.item_id)
8      where s.item_id = p_item_id;
9    --
10    v_stock cur_stock_reorder%ROWTYPE;
11    --
12    exc_zero_quantity EXCEPTION;
13    PRAGMA EXCEPTION_INIT(exc_zero_quantity, -1476);
14 begin
15    OPEN cur_stock_reorder;
16    FETCH cur_stock_reorder INTO v_stock;
17    IF cur_stock_reorder%NOTFOUND THEN
18      RAISE no_data_found;
19    END IF;
20    CLOSE cur_stock_reorder;
21    --
22    IF v_stock.stock_level >= v_stock.reorder_level THEN
23      -- Stock is not low enough to warrant an order
24      [b]RAISE_APPLICATION_ERROR(-20000, 'Stock has not reached re-order level yet!');[/b]
25    END IF;
26    --
27    IF v_stock.stock_level + p_quantity > v_stock.reorder_limit THEN
28      -- Required amount is over-ordering
29

its nice article, have put up this one the blog
site,Nah, I don't have time to blog, but if one of the other Ace's/Experts wants to copy it to a blog with reference back to here (and all due credit given ;)) then that's fine by me.
I'd go for a book like "Selected articles by OTN members" or something. Does anybody have a list of links of all those mentioned articles?Just these ones I've bookmarked...
Introduction to regular expressions ... by CD
When your query takes too long ... by Rob van Wijk
How to pipeline a function with a dynamic number of columns? by ascheffer
PL/SQL 101 : Exception Handling by BluShadow

Delete Statement Exception Handling

Hi guys,
I have a problem in my procedure. There are 3 parameters that I am passing into the procedure. I am matching these parameters to those in the table to delete one record at a time.
For example if I would like to delete the record with the values ('900682',3,'29-JUL-2008') as parameters, it deletes the record from the table but then again when I execute it with the same parameters it should show me an error message but it again says 'Deleted the Transcript Request.....' Can you please help me with this?
PROCEDURE p_delete_szptpsr_1 (p_shttran_id IN saturn.shttran.shttran_id%TYPE,
p_shttran_seq_no IN saturn.shttran.shttran_seq_no%TYPE,
p_shttran_request_date IN saturn.shttran.shttran_request_date%TYPE) IS
BEGIN
DELETE FROM saturn.shttran
WHERE shttran.shttran_id = p_shttran_id
and shttran.shttran_seq_no = p_shttran_seq_no
and trunc(shttran_request_date) = trunc(p_shttran_request_date);
DBMS_OUTPUT.PUT_LINE('Deleted the Transcript Request Seq No (' || p_shttran_seq_no || ') of the Student (' || p_shttran_id ||') for the requested date of (' || p_shttran_request_date ||')');
COMMIT;
EXCEPTION WHEN NO_DATA_FOUND THEN
DBMS_OUTPUT.PUT_LINE('Error: The supplied Notre Dame Student ID = (' || p_shttran_id ||
'), Transcript Request No = (' || p_shttran_seq_no || '), Request Date = (' || p_shttran_request_date || ') was not found.');
END p_delete_szptpsr_1;
Should I have a SELECT statement to use NO_DATA_FOUND ???

A DELETE statement that deletes no rows (just like an UPDATE statement that updates no rows) is not an error to Oracle. Oracle won't throw any exception.
If you want your code to throw an exception, you'll need to write that logic. You could throw a NO_DATA_FOUND exception yourself, i.e.
IF( SQL%ROWCOUNT = 0 )
THEN
RAISE no_data_found;
END IF;If you are just going to catch the exception, though, you could just embed whatever code you would use to handle the exception in your IF statement, i.e.
IF( SQL%ROWCOUNT = 0 )
THEN
<<do something about the exception>>
END IF;In your original code, your exception handler is just a DBMS_OUTPUT statement. That is incredibly dangerous in real production code. You are relying on the fact that the client has enabled output, that the client has allocated a large enough buffer, that the user is going to see the message, and that the procedure will never be called from any piece of code that would ever care if it succeeded or failed. There are vanishingly few situations where those are safe things to rely on.
Justin

Exception handling is not working in GCC compile shared object

Hello,
I am facing very strange issue on Solaris x86_64 platform with C++ code compiled usging gcc.3.4.3.
I have compiled shared object that load into web server process space while initialization. Whenever any exception generate in code base, it is not being caught by exception handler. Even though exception handlers are there. Same code is working fine since long time but on Solaris x86, Sparc arch, Linux platform
With Dbx, I am getting following stack trace.
Stack trace is
dbx: internal error: reference through NULL pointer at line 973 in file symbol.cc
[1] 0x11335(0x1, 0x1, 0x474e5543432b2b00, 0x59cb60, 0xfffffd7fffdff2b0, 0x11335), at 0x11335
---- hidden frames, use 'where -h' to see them all ----
=>[4] __cxa_throw(obj = (nil), tinfo = (nil), dest = (nil), , line 75 in "eh_throw.cc"
[5] OBWebGate_Authent(r = 0xfffffd7fff3fb300), line 86 in "apache.cpp"
[6] ap_run_post_config(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0x444624
[7] main(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0x42c39a
I am using following link options.
Compile option is
/usr/sfw/bin/g++ -c -I/scratch/ashishas/view_storage/build/coreid1014/palantir/apache22/solaris-x86_64/include -m64 -fPIC -D_REENTRANT -Wall -g -o apache.o apache.cpp
Link option is
/usr/sfw/bin/g++ -shared -m64 -o apache.so apache.o -lsocket -lnsl -ldl -lpthread -lthread
At line 86, we are just throwing simple exception which have catch handlers in place. Also we do have catch(...) handler as well.
Surpursing things are..same issue didn't observe if we make it as executable.
Issue only comes if this is shared object loaded on webserver. If this is plain shared object, opened by anyother exe, it works fine.
Can someone help me out. This is completly blocking issue for us. Using Solaris Sun Studio compiler is no option as of now.

shared object that load into web server process space
... same issue didn't observe if we make it as executable.When you "inject" your shared object into some other process a well-being of your exception handling depends on that other process.
Mechanics of x64 stack traversing (unwind) performed when you throw the exception is quite complicated,
particularly involving a "nearly-standartized" Unwind interface (say, Unwind_RaiseException).
When we are talking about g++ on Solaris there are two implementations of unwind interface, one in libc and one in libgcc_s.so.
When you g++-compile the executable you get it directly linked with libgcc_s.so and Unwind stuff resolves into libgccs.
When g++-compiled shared object is loaded into non-g++-compiled executable's process _Unwind calls are most likely already resolved into Solaris libc.
Thats why you might see the difference.
Now, what exactly causes this difference can vary, I can only speculate.
All that would not be a problem if _Unwind interface was completely standartized and properly implemented.
However there are two issues currently:
* gcc (libstdc++ in particular) happens to use additional non-standard _Unwind calls which are not present in Solaris libc
naturally, implementation details of Unwind implementation in libc differs to that of libgccs, so when all the standard _Unwind
routines are resolved into Solaris version and one non-standard _Unwind routine is resolved into gcc version you get a problem
(most likely that is what happens with you)
* libc Unwind sometimes is unable to decipher the code generated by gcc.
However that is likely to happen with modern gcc (say, 4.4+) and not that likely with 3.4.3
Btw, you can check your call frame to see where _Unwind calls come from:
where -h -lIf you indeed stomped on "mixed _Unwind" problem then the only chance for you is to play with linker
so it binds Unwind stuff from your library directly into libgccs.
Not tried it myself though.
regards,
__Fedor.

Exception handling to catch the outcome of a select

Hello,
I want to use exception handling to exit me out of a function module. I want to have one exception for all errors.
For example, if this select statement does not work, how do I finish up this code to make it work.
error type cx_bsx
try
select * from t001 where BUKRS = '!@#$'
catch <not sure what> into INTO error
raise exception error
endtry.
When I use cx_bsx with the catch, nothing happens even though the select statement fails. Basically I want the catch to work in the same manner as this:
if sy-subrc ne 0.
raise error_table_read.
endif.

If this code is in a function module, then why not just use the function module exceptions.
if sy-subrc ne 0.
raise error_table_read.
endif.
What are you gaining by "catching" this exception in the function module. By using the "exceptions" part of the function module, you are passing this exception back to the calling program.
Regards,
Rich Heilman

Info on JNI exception handling

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